P2-100 Determination of Growth Potential of Salmonella and Listeria monocytogenes in the Pulp of Eight Exotic Fruits

Tuesday, August 2, 2016
America's Center - St. Louis
Beatriz Severino da Silva, University of Campinas (UNICAMP), Campinas, Brazil
Marianna Miranda Furtado, University of Campinas (UNICAMP), Campinas, Brazil
Ana Carolina Rezende, University of Campinas (UNICAMP), Campinas, Brazil
Anderson de Souza Sant'Ana, University of Campinas (UNICAMP), Campinas, Brazil
Introduction: In recent years, an increase in the number of outbreaks associated with consumption of fresh fruit has been reported. There are no published data on the fate of Salmonella and Listeria monocytogenes in several exotic fruits. 

Purpose: The purpose of this study was to determine the growth potential (δ) of Salmonella spp. and L. monocytogenes in the pulps of exotic fruits stored at 10, 20, 30 and 37°C.

Methods: Pulp samples of jenipapo, umbu, maná, cajá-manga, physalis, feijoa, cupuaçu and abiu were separately inoculated with a cocktail of three and two strains of Salmonella spp. and L. monocytogenes. High-acid and low-acid fruits were inoculated with 106 CFU/g and 103 CFU/g of cocktails of each microorganism, respectively. After inoculation and homogenization, pulps were stored at 10, 20, 30 and 37°C, and counts of Salmonella and L. monocytogenes were done in MLCB and Oxford agars in 0, 2, 4, 6, 8, 10 and 12 h. The δ was determined by the difference between the counts at the end (12 h) (log CFU/g) and at the beginning (time “zero”) (log CFU/g) of storage period.

Results: Both Salmonella and L. monocytogenes were able to grow in abiu pulp (pH> 6.10) at 10-37°C. These pathogens lost viability in umbu and jenipapo pulps (3.7-6.2 log reductions within 2 h, respectively) regardless of storage temperature. In mana, cajá-manga and cupuassu these pathogens lost viability at 30 and 37 ºC/2-8 h, but survived at 10 and 20°C during 8-12 h. In cupuassu, Salmonella and L. monocytogenes were inactivated after 8 h at 20°C while in physalis and feijoa they survived for 12 h in all storage conditions.

Significance: The knowledge on the δ of pathogens in exotic fruits is important to allow measures to be taken to safeguard public health.